FR3030551A1 - METHOD FOR MANUFACTURING CONTROLLED EXPANSION CMP POLISHING PAD - Google Patents

Abstract

The invention provides a method of manufacturing a polishing pad suitable for planarizing at least one of semiconductor, optical and magnetic substrates, wherein a liquid polyurethane material is formed from a molecular molecule. Isocyanate terminator and a curing agent. The liquid polyurethane material has a T gel temperature and contains fluid-loaded polymeric microspheres which are a mixture of pre-expanded and unexpanded fluid-loaded polymeric microspheres each having a temperature at which the diameter of the polymeric microspheres charged with pre-expanded and unexpanded fluid increases and a temperature at which gas escapes to reduce the diameter of the expanded and unexpanded fluid-laden polymeric microspheres. The liquid polyurethane material is then cured into a polyurethane matrix that contains pre-expanded and expanded fluid-laden polymeric microspheres.

Description

BACKGROUND [0001] The present invention relates to the manufacture of polishing pads useful for polishing and planarizing semiconductor, optical and magnetic substrates. [0002] Polyurethane buffers are the main buffer type for a variety of demanding precision polishing applications. These polyurethane buffers are effective for polishing silicon wafers, pattern wafers, flat panel display devices and magnetic storage disks. In particular, polyurethane buffers have the necessary mechanical integrity and chemical resistance for most polishing operations used to make integrated circuits. For example, polyurethane buffers have high mechanical strength to resist tearing; abrasion resistance to avoid wear problems during polishing; and stability to resist attack by highly acidic and strongly basic polishing solutions. [0003] The production of semiconductors typically involves several chemical mechanical planarization (CMP) processes. In each CMP process, a polishing pad in combination with a polishing solution, such as a suspension containing an abrasive or a non-abrasive reactive liquid, removes excess material in a manner that planarizes or maintains flatness to receive a layer. subsequent. The stacking of these layers combines in a way that forms an integrated circuit. The fabrication of these semiconductor devices is becoming increasingly complex due to requirements for devices having higher operating speeds, lower leakage currents, and reduced power consumption. In terms of device architecture, this translates into finer element geometries and increased metallization levels. In some applications, these design requirements for increasingly stringent devices result in the adoption of an increased number of tungsten interconnection pads or vias in combination with new dielectric materials having more dielectric constants. bass. The diminished physical properties, which are frequently associated with low k and ultra-low k materials, in combination with the increased complexity of the devices have led to greater demands for CMP consumables, such as buffers and buffers. polishing solutions. [0004] In order to maintain a constant production of wafers, semiconductor manufacturers have for years been practicing in situ packaging with diamond discs. In situ packing cuts the top surface of polishing pads during polishing. A one-to-one-hundred-per-cent in-situ diamond conditioning process conditions throughout the polishing process. A fifty percent in-situ conditioning process conditions during half of the polishing process. This conditioning process is essential to roughen the polishing surface to maintain the rate of shrinkage by preventing smoothing of the polishing pad. In addition, these buffers must polish with constant speeds on hundreds of slabs. The casting of the polyurethane into cakes and the cutting of the cakes into several thin polishing pads have proven to be an effective method for producing polishing pads having consistent reproducible polishing properties. Reinhardt et al., U.S. Patent No. 5,578,362, describe the use of polymeric microspheres to improve planarization while maintaining a low defect. Unfortunately, commercial polyurethane pads produced with this structure often have speeds that are sensitive to the diamond packaging tool and the packaging process. In particular, as the diamonds wear out on the conditioning tool, they dig deeper channels into the polishing pad and these shallower channels can lead to lower polishing removal rates. In interlayer dielectric polishing (ILD) with a slurry of fumed silica, the removal rate (VR) of a polishing pad is very sensitive to conditioning with diamonds. Without in-situ conditioning, RV deteriorates rapidly during polishing of a few patties, see Figure 1. Although one hundred percent in-situ conditioning is typically used in polishing ILD with a fumed silica suspension, VR's high sensitivity to conditioning can still lead to a variation in performance as a result of wear of the conditioning disc during the life of the tampon. As a result, there is a need for a polishing pad having reduced sensitivity to conditioning without sacrificing its polishing efficiency. In addition, there is a need to develop an efficient method for making such CMP polishing pads and other CMP polishing pads.

SUMMARY OF THE INVENTION [0007] One aspect of the invention provides a method of making a polishing pad suitable for planarizing at least one of the semiconductor, optical and magnetic substrates, the method comprising the following : obtaining a liquid polyurethane material formed from an isocyanate-terminated molecule and a curing agent, the liquid polyurethane material having a T gel temperature and containing fluid-filled polymeric microspheres, the polymeric microspheres fluid loaded are a mixture of pre-expanded and unexpanded fluid-loaded polymeric microspheres, the pre-expanded and unexpanded fluid-loaded polymeric microspheres both having a temperature at which the diameter of the polymeric microspheres loaded with pre-expanded fluid -expansed and unexpanded increases at temperatures equal to or greater than the temperature and a temperature T. at which a gas escapes through the pre-expanded and unexpanded fluid-charged polymeric microspheres to reduce the diameter of the expanded and unexpanded fluid-laden polymeric microspheres, the temperature Wherein the unexpanded fluid-laden polymeric microspheres are below the temperature and the liquid polyurethane material; casting the liquid polyurethane material containing the mixture of pre-expanded and unexpanded fluid-loaded polymeric microspheres to react the isocyanate-terminated molecule and the curing agent; heating the mixture of pre-expanded and unexpanded fluid-loaded polymeric microspheres in the liquid polyurethane material to a temperature of at least 7 unexpanded fluid-laden polymeric microspheres to increase the diameter of the polymeric microspheres charged with unexpanded fluid, the heating being up to a temperature below the temperature at which a gas escapes through the pre-expanded and unexpanded fluid-loaded polymeric microspheres, the heating being intended to form a mixture of polymeric microspheres charged with pre-expanded and expanded fluid in the liquid polyurethane material; curing the mixture of pre-expanded and expanded fluid-charged polymeric microspheres in the liquid polyurethane material to solidify the liquid polyurethane material into a polyurethane matrix containing the pre-expanded and expanded fluid-loaded polymeric microspheres; and finishing the polishing pad from the cured polyurethane matrix containing the pre-expanded and expanded fluid-loaded polymeric microspheres wherein the final diameter of the pre-expanded and expanded fluid-loaded polymeric microspheres is less than that obtained from the temperature Trn. in air and most of the fluid contained in the pre-expanded and unexpanded fluid-loaded polymeric microspheres remains in the pre-expanded and expanded fluid-laden polymeric microspheres. Another aspect of the invention provides a method of manufacturing a polishing pad suitable for planarizing at least one of the semiconductor, optical and magnetic substrates, the method comprising the following: of a liquid polyurethane material formed from an isocyanate-terminated molecule and a curing agent, the liquid polyurethane material having a Tgei temperature and containing fluid-loaded polymeric microspheres, the fluid-loaded polymeric microspheres are a mixture of pre-expanded and unexpanded fluid-loaded polymeric microspheres loaded with isobutane, isopentane or a mixture of isobutane and isopentane, the pre-expanded and unexpanded fluid-loaded polymeric microspheres having the both to a temperature at which the diameter of the polymeric microspheres loaded with pre-expanded and unexpanded fluid It increases at temperatures equal to or higher than the temperature, temperature, and temperature. wherein a gas escapes through the pre-expanded and unexpanded fluid-loaded polymeric microspheres to reduce the diameter of the expanded and unexpanded fluid-laden polymeric microspheres, the Lb.temperature, unexpanded fluid-laden polymeric microspheres being lower than the temperature; el liquid polyurethane material; casting the liquid polyurethane material containing the mixture of pre-expanded and unexpanded fluid-loaded polymeric microspheres to react the isocyanate-terminated molecule and the curing agent; heating the mixture of pre-expanded and unexpanded fluid-filled polymeric microspheres in the liquid polyurethane material to a temperature of at least T3; unexpanded fluid-laden polymeric microspheres to increase the diameter of the charged polymeric microspheres of unexpanded fluid, the heating being up to a temperature below the temperature Tni 'at which a gas escapes through the pre-expanded and unexpanded fluid-charged polymeric microspheres, the heating being intended to form a mixture of pre-expanded and expanded polymeric fluid-loaded polymeric microspheres in the liquid polyurethane material; curing the mixture of pre-expanded and expanded fluid-charged polymeric microspheres in the liquid polyurethane material to solidify the liquid polyurethane material into a polyurethane matrix containing the pre-expanded and expanded fluid-loaded polymeric microspheres; and finishing the polishing pad from the cured polyurethane matrix containing the pre-expanded and expanded fluid-loaded polymeric microspheres where the final diameter of the pre-expanded and expanded fluid-loaded polymeric microspheres is less than that obtained from the temperature in the air and most of the fluid contained in the pre-expanded and unexpanded fluid-loaded polymeric microspheres remains in the pre-expanded and expanded fluid-laden polymeric microspheres.

According to a particular feature of the present invention, the method includes the further step of incorporating the pre-expanded and unexpanded fluid-laden polymeric microsphere mixture into the liquid polyurethane material prior to casting. According to another particular feature of the present invention, the Tna temperature, unexpanded fluid-laden polymeric microspheres is at least 5 ° C lower than the Tg temperature of the liquid polyurethane material. According to yet another particular feature of the present invention, the casting is carried out in a cake mold to form a polyurethane cake structure, and the method includes the additional steps of removing the mold polyurethane cake structure and cutting off of the cake structure in multiple sheets of polyurethane, and the formation of polishing pads from the polyurethane sheets.

According to yet another particular feature of the present invention, the casting includes pouring the liquid polyurethane material and the mixture of pre-expanded and expanded fluid-filled polymeric microspheres around a transparent block and forming the polishing pad includes a transparent window in the polishing pad.

DESCRIPTION OF THE DRAWINGS [0009] FIG. 1 is a graphical representation of the shrinkage speed at λ (10-10 m) / min as a function of the number of slabs after stopping the conditioning in situ for a suspension of fumed silica. Semi-SperseTm 25E (SS25). (Semi-Sperse is a registered trademark of Cabot Microelectronics Corporation.) FIG. 2 is a graphical representation of the average shrinkage speed in λ / min and the non-uniformity among wafers (NUG) (° / 0). ) for the polishing of ILD. FIG. 3 is a scanning electron microscopy (SEM) view of pre-expanded and unexpanded fluid-loaded microspheres at a concentration of 8% by weight. [0012] Fig. 4 is a SEM of pre-expanded and unexpanded fluid-loaded microspheres at a concentration of 5.25 ° A) by weight formed with a MbOCA curing agent. FIG. 4A is a graphical representation of the pore size distribution measured in micrometers for the polishing pad of FIG. 4. FIG. 5 is a SEM of microspheres loaded with pre-expanded and non-expanded fluid. expanded at a concentration of 5.25 ° A) by weight formed with a hardening agent MbOCA mixed with a multifunctional polyol. FIG. 5A is a graphical representation of the pore size distribution measured in micrometers for the polishing pad of FIG. 5. FIG. 6 is a graphical representation of the relative viscosity as a function of solids in FIG. volume fraction according to a modified Einstein-Guth-Gold equation. FIG. 7 is a graphical representation of the relative viscosity as a function of the weight percent of polymeric microspheres for pre-expanded, unexpanded polymeric microspheres, and mixtures of pre-expanded and non-expanded polymeric microspheres. expanded. DETAILED DESCRIPTION [0018] The invention provides a polishing pad suitable for planarizing at least one of semiconductor, optical and magnetic substrates. The polishing pad has a higher polishing surface, comprising a product of the reaction of an isocyanate-terminated prepolymer and a cure system. The upper polishing layer further comprises polymeric microspheres at a level of greater than 4 to less than 8 percent by weight of the prepolymer. These polishing pads have a higher shrinkage rate, better uniformity among wafers, and reduced process sensitivity. [0019] The polishing pad contains 4.2 to 7.5 percent by weight of fluid loaded microspheres in the prepolymer. Preferably, the polishing pad contains 4.5 to 7.5 percent by weight of fluid loaded microspheres in the prepolymer. Most preferably, the polishing pad contains 5 to 7.5 percent by weight of fluid loaded microspheres in the prepolymer. This leads to a polishing pad having low density or high porosity with controlled pore size. For example, the final density can be from 0.5 to 0.75 g / cm 3. Preferably, the final density is 0.5 to 0.65 g / cm 3. The fluid charge of the microspheres may be a gas, a liquid or a combination of gas and liquid. If the fluid is a liquid, the preferred fluid is water, such as distilled water which contains only accidental impurities. For the purposes of the present invention, the term microsphere includes envelopes having an imperfect spherical shape; for example, these envelopes have a shape that appears to be semi-hemispherical when they are cut open and observed with a SEM. If the fluid is a gas, air, nitrogen, argon, carbon dioxide or a combination thereof is preferred. For some microspheres, the gas may be an organic gas, such as isobutane. Preferably, the fluid is isobutane, isopentane or a combination of isobutane and isopentane. The isobutane trapped in the polymeric microsphere is a gas at room temperature (25 ° C) and above, depending on the internal pressure in the polymeric shell. The isopentane trapped in the polymeric microsphere is a combination of liquid and gas at room temperature. At temperatures of about 30 ° C and above, the isopentane becomes a gas, depending on the internal pressure in the polymeric shell. A polymeric envelope encloses the fluid; and typically the polymeric shell contains a gas under pressure. Specific examples of polymeric shells include polyacrylonitrile / methacrylonitrile shells and polyvinylidene dichloride / polyacrylonitrile shells. In addition, these envelopes may incorporate inorganic particles, such as silicates, calcium-containing or magnesium-containing particles. These particles facilitate the separation of the polymeric microspheres. These fluid-loaded microspheres typically have a final average diameter of 10 to 80 μm after expansion and preferably 20 to 60 μm. The pre-expanded polymeric microspheres typically grow from 10 to 60 percent to a final average diameter of 20 to 150 μm. However, the unexpanded polymeric microspheres typically grow from 1000 to 10,000 percent to a final diameter of 20 to 150 μm. The resulting polymeric microsphere mixture in the solidified polymeric matrix has a final average diameter of 10 to 80 μm after expansion and preferably 20 to 60 μm. [0021] The polishing pad optionally contains regions containing silica or alkaline earth metal oxides (group 30305 of the periodic table) distributed in each of the polymeric microspheres. These regions containing silica or alkaline earth metal oxides may be particles or have a structure containing elongated alkaline earth metal oxides. Typically, regions containing alkaline earth metal oxides are particles included or attached to the polymeric microspheres. The average particle size of the particles containing alkaline earth metal oxides is typically 0.01 to 3 μm. Preferably, the average particle size of the particles containing alkaline earth metal oxides is 0.01 to 2 μm. These particles containing alkaline earth metal oxides are spaced to cover less than 50 percent of the outer surface of the polymeric microspheres. Preferably, the regions containing alkaline earth metal oxides cover from 1 to 40 percent of the surface area of the polymeric microspheres.

Particularly preferably, the regions containing alkaline earth metal oxides cover 2 to 30 percent of the surface area of the polymeric microspheres. Microspheres containing silica or containing alkaline earth metal oxides have a density of 5 g / liter to 1000 g / liter. Typically, the microspheres containing alkaline earth metal oxides have a density of 10 g / liter to 1000 g / liter. [0022] Typical polymer polishing pad matrix materials include polycarbonates, polysulfones, polyamides, ethylene copolymers, polyethers, polyesters, polyether-polyester copolymers, acrylic polymers, poly ( methyl methacrylate), polyvinyl chloride, polyethylene copolymers, polybutadiene, polyethyleneimine, polyurethanes, polyethersulfone, polyetherimide, polyketones, epoxides, silicones, copolymers thereof and mixtures thereof. Preferably, the polymeric material is a polyurethane and may be a crosslinked polyurethane or an uncrosslinked polyurethane. For the purposes of this specification, "polyurethanes" are derivatives of difunctional or polyfunctional isocyanates, for example polyetherureas, polyisocyanurates, polyurethanes, polyureas, polyurethaneures, their copolymers and mixtures thereof. [0023] Preferably, the polymeric material is a block or segmented copolymer capable of separating into rich phases in one or more blocks or one or more segments of the copolymer. Most preferably, the polymeric material is a polyurethane. The cast polyurethane matrix materials are particularly suitable for planarizing semiconductor, optical and magnetic substrates. One approach to control the polishing properties of a buffer is to modify its chemical composition. In addition, the choice of raw materials and manufacturing process affects the morphology of the polymers and the final properties of the material used to produce polishing pads. [0024] Preferably, the production of urethanes comprises the preparation of an isocyanate-terminated urethane prepolymer from a polyfunctional aromatic isocyanate and a prepolymer polyol. For purposes of this specification, the term prepolymer polyol includes diols, polyols, polyol diols, copolymers thereof, and mixtures thereof. Preferably, the prepolymer polyol is selected from the group consisting of polytetramethylene ether glycol [PTMEG], polypropylene ether glycol [PPG], ester-based polyols such as ethylene or butylene adipates, copolymers thereof, and mixtures thereof. Examples of polyfunctional aromatic isocyanates include 2,4-toluene diisocyanate, 2,6-toluenediisocyanate, 4,4'-diphenyl methanediisocyanate, naphthalene-1,5-diisocyanate, toluidediediisocyanate, para-phenylenediisocyanate, xylylene diisocyanate and their mixtures.

The polyfunctional aromatic isocyanate contains less than 20 percent by weight of aliphatic isocyanates, such as 4,4'-dicyclohexyl methane diisocyanate, isophorone diisocyanate and cyclohexane diisocyanate. Preferably, the polyfunctional aromatic isocyanate contains less than 15 percent by weight of aliphatic isocyanates and more preferably, less than 12 percent by weight of aliphatic isocyanate. Examples of prepolymer polyols include polyether polyols, such as poly (oxytetramethylene) glycol, poly (oxypropylene) glycol and mixtures thereof, polycarbonate polyols, polyester polyols, polycaprolactone polyols and mixtures thereof. The exemplary polyols can be blended with low molecular weight polyols, including ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butanediol, 1,3-butanediol, 2-methyl-1,3-propanediol, 1,4-butanediol, neopentyl glycol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, diethylene glycol, Dipropylene glycol, tripropylene glycol and mixtures thereof. Preferably the prepolymer polyol is selected from the group comprising polytetramethylene ether glycol, polyester polyols, polypropylene ether glycols, polycaprolactone polyols, their copolymers and mixtures thereof. If the prepolymer polyol is PTMEG, a copolymer thereof, or a mixture thereof, the isocyanate-terminated reaction product preferably has a weight percentage of unreacted NCO in a range of 8. 0 to 20.0 percent by weight. For polyurethanes formed with PTMEG or PTMEG mixed with PPG, the weight percent of preferable NCO is in the range of 8.75 to 12.0; and most preferably it is from 8.75 to 10.0. Specific examples of polyols of the PTMEG family are: Terathane® 2900, 2000, 1800, 1400, 1000, 650 and 250 Invista; Polymeg® 2900, 2000, 1000, 650 Lyondell; PolyTHFC) 650, 1000, 2000 from BASF, and lower molecular weight species such as 1,2-butanediol, 1,3-butanediol, and 1,4-butanediol. If the prepolymer polyol is a PPG, a copolymer thereof or a mixture thereof, the isocyanate-terminated reaction product has most preferably a weight percent of unreacted NCO in a range of 7.9 to 15.0 ° A) by weight. Specific examples of PPG polyols are: Arcol® PPG-425, 725, 1000, 1025, 2000, 2025, 3025 and 4000 from Bayer; Voranol® 1010L, 2000L, and P400 from Dow; Desmophen® 1110BD, Acclaim® Polyol 12200, 8200, 6300, 4200, 2200, both product lines being from Bayer. If the prepolymer polyol is an ester, a copolymer thereof or a mixture thereof, the isocyanate-terminated reaction product has most preferably a weight percent of unreacted NCO in a range of 6.5 to 13.0. Specific examples of the polyol ester are: Milster 1, 11, 2, 23, 132, 231, 272, 4, 5, 510, 51, 7, 8, 9, 10, 16, 253 of Polyurethane Specialties Company, Inc .; Desmophen® 1700, 1800, 2000, 2001K5, 2001K2, 2500, 2501, 2505, 2601, PE65B from Bayer; Rucoflex S-1021-70, S-1043-46, S-1043-55 from Bayer. Typically, the prepolymer reaction product is reacted or cured with a polyol, polyamine, alcoholamine curing agent, or a mixture thereof. For the purposes of the present invention, polyamines include diamines and other multifunctional amines. Examples of polyamine curing agents include aromatic diamines or polyamines, such as 4,4'-methylene-bis-o-chloroaniline [MbOCA], 4,4'-methylene-bis- (3-chloro-2), 6-diethylaniline) [MCDEA]; methyltoluene diamine; tri methylene glycol di-p-aminobenzoate; poly (tetramethylene oxide) di-p-aminobenzoate; poly (tetramethylene oxide) mono-paminobenzoate; poly (propylene oxide) di-p-aminobenzoate; poly (propylene oxide) mono-p-aminobenzoate; 1,2-bis (2-aminophenylthio) ethane; 4,4'-methylene-bisaniline; diethyltoluenediamine; 5-tert-butyl-2,4- and 3-tert-butyl-2,6-toluenediamine; 5-tert-amyl-2,4- and 3-tert-amyl-2,6-toluenediamine and chloro-toluenediamine. Optionally, it is possible to make urethane polymers for polishing pads with a single mixing step, which avoids the use of prepolymers. The components of the polymer used to produce the polishing pad are preferably chosen so that the morphology of the resulting buffer is stable and easily reproducible. For example, when 4,4'-methylene-bis-o-chloroaniline [MbOCA] is mixed with a diisocyanate to form polyurethane polymers, it is often advantageous to control the levels of monoamine, diamine and triamine. . Control of the proportion of mono-, di- and triamines contributes to maintaining the chemical ratio and the molecular weight of the resulting polymer in a constant range. In addition, it is often important to control additives such as antioxidants, and impurities such as water for constant production. For example, as the water reacts with the isocyanate to form gaseous carbon dioxide, control of the water concentration can affect the concentration of the carbon dioxide bubbles that form pores in the polymer matrix. The reaction of the isocyanate with the accidental water also reduces the isocyanate available to react with the chain extender, which modifies the stoichiometry as well as the level of crosslinking (if there is an excess of isocyanate groups) and the molecular weight of the resulting polymer. The polymeric polyurethane material is preferably formed from a prepolymer reaction product of toluene diisocyanate and polytetramethylene ether glycol with an aromatic diamine. Most preferably the aromatic diamine is 4,4'-methylene-bis-o-chloroaniline or 4,4'-methylene-bis- (3-chloro-2,6-diethylaniline). Preferably, the prepolymer reaction product has 6.5 to 15.0 weight percent unreacted NCO. Examples of suitable prepolymers in this unreacted NCO range include: Imuthane® PET-70D, PHP-70D, PET-75D, PHP-75D, PPT-75D, PHP-80D prepolymers manufactured by COIM USA , Inc. and Adiprene®, LFG740D, LF700D, LF750D, LF751D, LF753D, L325 prepolymers manufactured by Chemtura. In addition, mixtures of other prepolymers, besides those listed above, could be used to achieve appropriate levels of unreacted NCO as a result of the mixing operation. Many of the prepolymers listed above, such as LFG740D, LF700D, LF750D, LF751D, and LF753D are low free isocyanate prepolymers that have less than 0.1 weight percent free TDI monomer and have a molecular weight distribution of Prepolymers more constant than conventional prepolymers, so that they facilitate the formation of polishing pads having excellent polishing characteristics. This improved consistency of the molecular weight of the prepolymers and this low free isocyanate content give a more even polymer structure, and contribute to improved polishing pad consistency. For most prepolymers, the low free isocyanate monomer content is preferably less than 0.5 percent by weight. In addition, "conventional" prepolymers which typically have higher reaction levels (i.e., more than one diisocyanate-capped polyol at each end) and higher levels of free toluenediisocyanate prepolymer should produce results. Similar. In addition, low molecular weight polyol additives, such as diethylene glycol, butanediol, and tripropylene glycol, facilitate control of the weight percent of unreacted NCO of the prepolymer reaction product. Similarly, the polymeric polyurethane material may be formed from a prepolymer reaction product of 4,4'-diphenylmethane diisocyanate (MDI) and polytetramethylene glycol with a diol. Most preferably, the diol is 1,4-butane diol (BDO). Preferably, the prepolymer reaction product has 6 to 13% by weight of unreacted NCO. Examples of suitable polymers with this unreacted NCO range include the following: Imuthane 27-85A, 27-90A, 27-95A, 27-52D, 27-58D from COIM USA and 5 Andur® IE-75AP , IE80AP, IE90AP, IE98AP, IE110AP from Anderson Development Company. In addition to controlling the percent by weight of unreacted NCO, the reaction product of the curing agent and prepolymer typically has a stoichiometric ratio of OH or NH 2 to NCO which does not reacted at 85 to 115 percent, preferably 90 to 100 percent. This stoichiometry could be obtained directly, by providing stoichiometric levels of raw materials, or indirectly by reacting a certain portion of the NCO with water on purpose or by exposure to accidental moisture. [0032] The polishing pad has a lower wear sensitivity due to the conditioning tool than most polishing pads. This is useful especially for combating the negative impact of diamond wear. The buffers of the invention can have a sensitivity to the conditioning tool (SC) of 0 to 2.6. Preferably the SC is 0 to 2. For the purposes of this invention, SC is defined as follows: 5c = (Equation 1) where SC is defined as the difference between the rate of removal of TEOS from cover to a package in situ 75% (T, 'Rd 7) and the coverage TEOS removal rate at a 50% in situ conditioning (VR GO divided by the coverage TEOS removal rate at a partial in situ conditioning of 50% by means of a fumed silica suspension having an average particle size of 0.1 μm at a concentration of 12.5 ° A) by weight with a pH of 10.5 (all after dilution with water distilled at a ratio of 1: 1) with a diamond conditioning tool having an average particle size of 150 μm, a pitch of 400 μm and a protrusion of 100 μm at a pressing force of the packaging tool of 4 μm. , 08 kg (9 lbs). The shrinkage rate values SC represent the shrinkage rate obtained after achieving permanent polishing or typically at least after about ten slabs. There are significant challenges in the production of CMP polishing pads with pre-expanded polymeric microspheres at a level greater than 4 percent by weight in the prepolymer, due to the exponential increase in the viscosity of the material. when the charge of the pre-expanded polymeric microspheres increases. The introduction of unexpanded polymeric microspheres which can expand due to the exothermic reaction of the prepolymer and the curing system not only reduces the viscosity of the material for easy processing but also leads to better product consistency and higher production efficiency. During production, a liquid polyurethane material has a Tgel temperature and contains polymeric microspheres charged with fluid. The fluid-loaded polymeric microspheres are a mixture of pre-expanded fluid-loaded polymeric microspheres and unexpanded fluid-laden polymeric microspheres. Both pre-expanded and unexpanded fluid-loaded polymeric microspheres have a temperature Tnar, at which the diameter of the pre-expanded and unexpanded fluid-loaded polymeric microspheres increases at temperatures equal to or greater than the TEtart temperature. In addition, they have a temperature T. at which gas escapes through the fluid-filled polymeric microspheres which reduces the diameter of the polymeric microspheres. Because this can form large gas bubbles in the polymer matrix and large bubbles can lead to polishing defects, casting at temperature or temperature above the temperature. T ,, 'is not a desirable situation. In order to grow the unexpanded polymeric microspheres, it is important that the unexpanded fluid-laden polymeric microsphere temperature be less than the temperature / liquid polyurethane material. Advantageously, the temperature of unexpanded fluid laden polymeric microspheres is at least 5 ° C lower than the temperature of the liquid polyurethane material. Advantageously, the temperature of the unexpanded fluid-laden polymeric microspheres is at least 10 ° C lower than the T gel temperature of the liquid polyurethane material. Since the pre-expanded fluid-loaded polymeric microspheres already have an effective average diameter, it is not necessary to increase it further and it is optional that the temperature of the pre-expanded fluid-loaded polymeric microspheres is less than the Tg1 temperature. liquid polyurethane material. The casting of the liquid polyurethane material containing the mixture of pre-expanded and unexpanded fluid-loaded polymeric microspheres causes the isocyanate-terminated molecule and the curing agent to react. The exothermic heat from the reaction heats the mixture of pre-expanded and unexpanded fluid-loaded polymeric microspheres in the liquid polyurethane material to a temperature at least equal to the unexpanded fluid-laden polymeric microspheres. increases the diameter of the unexpanded fluid-laden polymeric microspheres. Preferably this exothermic heat is the main heat source for causing the expansion of the polymeric microspheres. The heating is up to a temperature below the temperature T at which gas escapes through the pre-expanded and unexpanded fluid-laden polymeric microspheres. This heating forms a mixture of pre-expanded and expanded fluid-charged polymeric microspheres in the liquid polyurethane material. Optionally, incorporating the pre-expanded and unexpanded polymeric microsphere mixture into the liquid polyurethane material prior to casting improves the uniformity of the distribution of the polymeric microspheres. Curing the mixture of pre-expanded and expanded fluid-filled polymeric microspheres in the liquid polyurethane material solidifies the liquid polyurethane material into a polyurethane matrix containing the pre-expanded and expanded fluid-laden polymeric microspheres. Then, finishing the cured polyurethane matrix, containing the pre-expanded and expanded polysaccharged polymeric microspheres into a polishing pad by cutting, dressing, scribing, puncturing, and adding a sub-pad creates a finished product. For example, when casting in a mold, it is possible to cut the polishing pad into multiple polyurethane sheets and then form the polishing pads from the polyurethane sheets. The final diameter of the pre-expanded and expanded fluid-loaded polymeric microspheres in the polishing pad is less than that obtained from the T.sub.T in air and most of the fluid contained in the fluid-loaded polymeric microspheres. pre-expanded and unexpanded remains in pre-expanded and expanded polymeric fluid-loaded polymeric microspheres. [0037] In addition, it is important that the liquid polyurethane material has a low viscosity to facilitate casting in constant product configurations. The formation of a mixture of pre-expanded and unexpanded polymeric microspheres lowers the viscosity, which facilitates casting. This is particularly important when casting around objects such as transparent blocks used to form transparent windows in polishing pads. Only a pre-expanded mixture may lack the viscosity necessary for casting into simple shapes. Only an unexpanded blend can create a significant stress in a cake due to the large expansion of the unexpanded microspheres. These constraints can lead to a cracked or fractured polymeric matrix. In addition, it is advantageous that most of the heat required to expand the unexpanded polymeric microspheres is from an exothermic reaction used to create the polymeric matrix. However, a mixture of pre-expanded and unexpanded polymeric microspheres having a relative viscosity of 1.1 to 7 may have a sufficient viscosity for casting in combination with sufficient exothermic heat to create adequate porosity. Preferably, a relative viscosity of 3 to 7 provides a balanced combination of pourability and pore size. In addition, increasing the proportion of unexpanded polymeric microspheres to pre-expanded polymeric microspheres lowers viscosity which improves casting ability, but increases the residual stress in the cake, which can cause cake burst and other defects. Similarly, increasing the proportion of pre-expanded polymeric microspheres to unexpanded polymeric microspheres can increase the viscosity, making casting more difficult. Examples Example 1 [0038] Table 1 shows the composition of the polishing layer of two comparative examples no. Cl and no. C2 and two examples of the present invention no. 1 and no. 2. The isocyanate-terminated prepolymer 30305 used was Adiprene® L325, commercially available from Chemtura Corporation, with a typical unreacted isocyanate (NCO) of 9.1% by weight. The cure system was 4,4'-methylenebis (2-chloroaniline) (MbOCA) or a combination of MbOCA and Voralux® HF 505, a high molecular weight (MW) multifunctional polyol curing agent with six hydroxyl functionalities. and a MW of about 11000. The stoichiometry of the reaction, calculated from the molar ratio of total active hydrogen (as amine and hydroxyl functional groups in the curing system) to the isocyanate functional groups in the prepolymer was 0.87 for all the examples. The pre-expanded (DE) and unexpanded (DU) fluid-loaded polymeric microspheres were mixed with the prepolymer to form a premix. Expancel® 551DE40d42, Expancel® 461DE20d70, both of DE quality, and Expancel® 15 031DU40, DU quality, are commercially available from AkzoNobel. The amount of total polymeric microspheres ranged from 2.2 to 5.25 percent by weight in the premix (the mixture of prepolymer and polymeric microspheres).

Table 1: Example Hardening agent MbOCA Multi-functional hardening agent Diameter of pre-expanded microspheres ("lm) Pre-expanded microspheres Diameter of unexpanded microspheres (" lm after expansion) Microspheres, unexpanded Micro- (% in (% in (% in (% in weight) weight) Weight (wt) total weight (wt%) Cl 100 40 * 2.2 2,2 C2 75 25 20 ** 3.75 3.75 1 100 20 ** 3.75 40 *** 1.5 5.25 2 75 25 20 ** 3.75 40 *** 1.5 5.25 Adiprene® is a prepolymer of urethane produced by Chemtura Corporation. Adiprene L325 is an H12MDI / TDI urethane prepolymer with polytetramethylene ether glycol (PTMEG) having an unreacted NCO of 8.95 to 9.25% by weight. * 551DE40d42, ** 461DE20d70, and *** 031DE40 551DE40d42, 461DE20d70, and 031DE40 are fluid-filled polymeric microspheres produced by AkzoNobel under the trademark Expancel®. The polishing layer for all sample buffers was finished with superimposed circular (1010) and radial (R32) grooves (1010 + R32). A subaTM IV sub-pad of 1.02 mm (40 mil = 40 x 10-3 inches) thick was applied to the polishing layer. The circular grooves 1010 had a width of 0.51 mm (20 mils), a depth of 0.76 mm (30 mils) and a pitch of 3.05 mm (120 mils). The radial grooves R-32 were 32 uniformly spaced radial grooves having a width of 0.76 mm (30 mils) and a depth of 0.81 mm (32 mils). The slurry used was a fumed silica ILD3225 suspension, commercially available from Nitta Haas Incorporated, having an average particle size of about 0.1 μm, diluted with deionized water at a ratio of 1: 1 to 12.5 ° A) by weight of abrasive at the point of use (PU) for polishing. Polishing was performed on a 300 mm Reflexion (i) CMP polishing system from Applied Materials. The polishing conditions are summarized below. Polishing conditions: - Suspension: ILD3225 (1: 1 dilution with DI water at a 12.5% abrasive content, pH 10.5) - PU filter: Pall 1.5 μm - Suspension flow rate: 250 ml / min - Packaging Tool: PDA33A-3 from Kinik Company; diamond size 150 μm, not diamonds 400 μm, diamond protrusion 100 ± 15 μm. - Buffer run-in: 90/108 rpm (tray / conditioning disc), 5.4 kg (12 lbs) resting force for 20 minutes then 4.1 kg (9 lbs) for 10 minutes; high pressure rise (HPR) 30305 5 1 24 - During polishing: total in situ conditioning at a packing pressure of 4.1 kg (9 lbs) - Polishing: 93/87 rpm (tray / slab The oxide polishing was performed on TEOS oxide wafers formed by chemical vapor deposition (TEOS). decomposition product of tetraethyl orthosilicate). The withdrawal rates (VR) and non-uniformity among the wafers (NUG) are shown in Fig. 2 and are also summarized in Table 2. Table 2 VR Uniformity VR Microsphere VR Coherent of TEOS Polymers Among the Normalized total polishing wafers of Example ° A) by weight (Â / min) ° A) no. Cl 2.2 4546 3.5 100% C2 3.75 4685 2.8 103% 1 5.25 5002 2.6 110% 2 5.25 5066 2.5 111% 15 [0042] Figure 2 and the table 2 show an improved removal rate and NUG for the polishing pad of the invention. [0043] The polishing pads of the present invention (Examples 1 and 2), which contained more than 4% by weight of total polymeric microspheres in the premix, exhibited a TEOS withdrawal rate. higher and better uniformity among wafers than Comparative Examples (Examples No. Cl and C2) which had less than 4% by weight of total polymeric microspheres in the premix. Surprisingly, the polishing pads of the present invention had less sensitivity to the conditioning process combined with high polishing efficiency. Conditioning sensitivity (SC) is defined as the difference in RV at partial in situ conditioning of 75 ° A) and 50 ° A) divided by RV at 50% partial in situ conditioning. SC - (Equation 1) [0044] As shown in Table 3, the polishing pads of the present invention had an SC less than 1% while Comparative Example no. Cl had an SC of more than 3%. The reduced SC is critical for stable polishing performance because the conditioning discs wear out during the life of the pads. Table 3 TEOS Microsphere VR Coil (Â / min) Polymeric Sensitivity Total Polishing (SC) conditioning of ° A) Partial in-situ partial weight of partial 75% 50% Example 2.2 3890 3754 3.6% nr. Cl example 5.5 4864 4821 0.9% no. 1 example 5.25 4961 4970 0.2% no. Too much fluid-charged polymeric microspheres in the premix could cause blowholes in the polishing layer, resulting in a non-uniform product and possibly polishing performance that is not constant. . Figure 3 shows blowholes present at 8 ° A) by weight of fluid-filled polymeric microspheres. The sample in Fig. 3 had the same chemical composition (prepolymer and curing agent) as Comparative Example C1 and Example 1 shown in Table 1, but a larger charge of 8 ° fluid loaded polymeric microspheres. A) by weight of Expancel 031DU40. By comparison, the two examples no. 1 and no. 2 of the present invention exhibited a uniform pore structure in the polishing layer with a normal pore size distribution, as shown in FIGS. 4 and 5, respectively. Example 2 [0047] There have been significant challenges in casting polyurethane polishing pads loaded with high porosity polymeric microspheres (low density MV) into cake molds. The challenge became more exacerbated when an integrated window was considered. This was mainly due to the poor fluidity of a very viscous premix and the liquid polyurethane precursor. The viscosity of a charged system increases to a large extent with the increase in the volume fraction of a charge, see Figure 6 (Journal of Colloid Science, Vol 20, 267-277, 1965). David G. Thomas graphically represented the relative viscosity of a charged system with a volume fraction of filler (1) and obtained the following equation to predict the viscosity of a charged system. Figure 6 is a graphical representation of a modified Einstein-Guth-Gold equation that describes the viscosity of a slurry charged with spherical particles. 30 = 1 + 2.50 +10.0502 0.00273e16'60 (equation 2) where p is the viscosity of the loaded system, go, the viscosity of the unfilled material, 1 ± the relative viscosity, and (1) the fraction volume of the charge. A typical prepolymer density (MV) is about 1.05 g / cm 3. With a MV of polymer microspheres loaded with a given fluid, we can easily predict the viscosity increase of a premix at different load levels of fluid-loaded polymeric microspheres using Equation 2. The viscosity of the premix will increase significantly with increase in the charge of pre-expanded polymeric microspheres. The results presented in Table 4 relate to pre-expanded polymeric microspheres. Expancel 551DE40d42, Expancel 551DE20d60, and Expancel 461DE20d70 all allow to obtain numbers exceeding 40; to more than 8% by weight of fluid-filled polymeric microspheres. Table 4% by weight Relative viscosity of a charged system microspheres with polymers 551DE40d42 551DE20d60 461DE20d70 0 1.0 1.0 1.0 1 2.0 1.6 1.5 2 3.7 2.6 2.3 3 7.8 4.0 3.3 4 18 6.8 5,1 5 40 12 8.2 6 80 23 14 7 146 40 23 8 244 67 39 3 0 3 0 5 5 1 28 [0050] At a temperature of Using typical prepolymer from 50 to 70 ° C, most commercially available prepolymers without any filler have a viscosity in the range of 1 to 5 Pa.s (1000 to 5000 cP), as shown in Table 5. There are many challenges in handling a premix that has a viscosity substantially greater than 10,000 cps in a casting process, including defects such as flow patterns. Increasing the premix temperature to reduce viscosity is not feasible because the freeze time may become too short to sink a cake. As a result, normally the maximum loading with a charge in a premix is not greater than 4% by weight for Expancel 461DE20d70 polymeric microspheres or 2.5% by weight for Expancel polymeric microspheres. 551DE40d42. At such load levels, the relative viscosity of the premix relative to the unloaded prepolymer is about 5. In other words, the viscosity of the premix is about 5 times that of the unfilled prepolymer. Because of this limitation, the maximum volume porosity is typically less than 40% for a polishing pad with porosity generated by incorporation of conventional pre-expanded polymeric microspheres. This is reflected in significant challenges in the production of CMP polishing pads having an MV less than 0.70 g / cm 3 using pre-expanded polymeric microspheres.

Table 5 Typical viscosity of commercial prepolymers without any filler at different temperatures Prepolymer T range Typical Viscosity ° A) NCO (° C) (Pa.) (CP) Adiprene L325 8.95-9, 25 30 20 20000 50 5 5000 70 1 1000 Adiprene 750D 8.75-9.05 30 10.5 10500 60 1.250 1250 Adiprene 600D 7.1-7.4 30 6 6000 60 0.9 900 Adiprene LFG963A 5.55 To overcome the viscosity limitations of a prepolymer containing greater than 4 to less than 8% by weight of polymeric microspheres, the present invention provides a A process for producing a very high porosity polishing pad having bulk density values of less than 0.70 g / cm 3 without a significant increase in premix viscosity. The unexpanded polymeric microspheres occupy much less volume because of their high initial density values (close to those of a prepolymer). As a result, they do not contribute much to the increase in viscosity of the premix. These unexpanded polymeric microspheres can expand under the effect of heating including exothermic reaction of a polyurethane prepolymer with a cure system. As a result, it is possible to produce a very high porosity with buffer density values of less than 0.70 g / cc in a reproducible manner without the limitation of a high viscosity premix. 30305 5 1 30 [0053] Example no. 1 and the example no. 2 had a very uniform porous structure, as shown in FIGS. 4, 4A, 5 and 5A. The average pore size and standard deviation of Example No. 1, of the example no. 2 and comparative example no. Cl are presented in Table 6.

Table 6 Pore Size Layer Standard Deviation (μm) Polishing Average (μm) Example No. Cl 41 13 the example no. Example No. Figure 7 shows a comparison of the relative viscosities of a premix containing different types of fluid loaded polymeric microspheres. There are two viable approaches for maintaining the viscosity of a premix within a reasonable range with a loading of fluid loaded polymeric microspheres greater than 4 and less than 8% by weight. The first approach is to use only unexpanded polymeric microspheres, such as Expancel 031DU40 polymeric microspheres. The increase in viscosity will be less than 50% at a loading level of up to 8% by weight. An alternative is to use a combination of 20 pre-expanded and unexpanded polymeric microspheres. The amount of pre-expanded polymeric microspheres, such as Expancel 461DE20d70 polymeric microspheres, can be kept below 4% by weight to maintain a reasonable premix viscosity. With density values close to 1.0 g / cm 3, the unexpanded polymeric microspheres, such as Expancel 031DU40 polymeric microspheres, do not contribute much to the viscosity of the premix. At a total loading of fluid loaded polymeric microspheres of 8% by weight, it is possible to obtain a reduction of the order of magnitude of the viscosity of the premix by introducing unexpanded polymeric microspheres. as Expancel 031DU40.

Example 3 [0055] Pre-expanded or unexpanded fluid-loaded polymeric microspheres can expand when the temperature increases.

The degree of expansion is dependent on the temperature, the polymer composition of the polymeric shell, the boiling point of the encapsulated liquid and whether the polymeric microspheres are pre-expanded or unexpanded. Thermomechanical analysis (ATM) provides an excellent tool for measuring the expansion of different fluid-loaded polymeric microspheres. The ATM process was implemented on the Thermal Mechanical Analyzer Q400 thermomechanical analyzer manufactured by TA Instruments. A ceramic capsule with an internal diameter of 7.54 mm was placed on the sample platform of a Q400 TMA. An aluminum lid having an outer diameter of 6.6 mm was placed inside the cup on the platform. A 6.1 mm diameter quartz expansion probe was lowered into the capsule containing the lid with a preload of 0.06 N pressing force. The initial thickness of the sample was measured by the instrument and the resulting thickness was brought to zero by the instrument. The sample capsule and lid were then removed from the platform and the lid removed from the capsule. A small amount of fluid-loaded polymeric microspheres was placed in the capsule, and then the lid was inserted into the capsule. The capsule and lid were placed back on the ATM platform and the quartz probe was lowered into the capsule containing the sample and lid. The thickness was measured again and noted by the instrument. The ATM 30305 51 was then programmed for a rise in temperature from 30 ° C to 250 ° C with a rise rate of 3 ° C / min and a preload of 0.06 N. [0056] Expansion initiation (rna ,,), maximum expansion, and maximum expansion temperature (T ,,) are shown in Table 7 for some selected fluid-loaded polymeric microspheres. All polymeric microspheres expanded when heated to a temperature above their Tgurt temperature, including pre-expanded grades. [0057] The reaction exotherm generated during liquid polyurethane casting can easily raise the temperature of the reaction mixture well beyond 100 ° C before the material solidifies / gels, causing a significant expansion of polymeric microspheres. having suitable thermomechanical properties.

30305 5 1 33 Table 7 Polymeric microspheres _ (° c) Expansion _ ic \ maximum '"Expancel 551DE40d42 109 60% 131 Expancel 551DE20d60 103 40% 126 Expancel 461DE20d70 104 62% 128 Expancel 920DE40d30 122 14% 155 Expancel 920DE80d30 128 27% 169 Matsu motorcycle F-65DE 106 24% 158 Matsu motorcycle FN-80SDE 106 12% 135 Matsu motorcycle FN-100SSDE 109 17% 156 Matsu motorcycle F-190DE 155 29% 189 Matsu motorcycle FN-100SSD 137 940% 159 Matsu motorcycle F-30D 85 5445% 122 Matsu motorcycle F-36D 100 8300% 138 Matsu motorcycle F-48D 102 5297% 137 Expancel 031DU40 91 5235% 117 Expancel 461DU20 99 1966% 129 Expancel 930DU120 122 4989% 174 ratio 91 96% 128 Expancel 031DU40 / Expancel 461DE20d70 1/8 in weight ratio 90 145% 116 Expancel 031DU40 / Expancel 461DE20d70 1/4 in weight ratio 90 282% 116 Expancel 031DU40 / Expancel 461DE20d70 1/2 in weight ratio 90 308% 120 Expancel 031DU40 / Expancel 461DE20d70 1/1 in weight The temperature of the liquid polymer precursor at the gel point, Tel, must be greater than Tnar, so that the expansion of the fluid-laden polymeric microspheres occurs. Table 8 shows the percent expansion at different temperatures of different polymeric microspheres. There are different approaches for controlling Tgei such as changing the processing temperature or modifying the exotherm of the reaction by using a different NCO prepolymer at A). Compared with 8.9% NCO for 5 Adiprene LF750D and 9.1% NCO for Adiprene L325, Adiprene LFG963A has a lower NCO of 5.7%. When Adiprene LFG963A was hardened with MbOCA under the same conditions, Tged was 105 ° C, much lower than the Expancel T 031DU40, but higher than its T of 91 ° C. As a result, uniform porous structures were obtained without large bubbles larger than 100 μm. At 105 ° C, Expancel 031DU40 can expand 24 times its original volume, as shown in Table 8.

30305 5 1 Table 8 Polymeric Microspheres ° A) Expansion at temperature 115 (° C) 120 100 105 110 Matsu Motorcycle F-190DE 0% 0% 0% 0% 0% Matsu Motorcycle FN-100SSD 0% 0% 0 % 0% 0% Expancel 920DE40d30 0% 0% 0% 0% 0% Expancel 920DE80d30 0% 0% 0% 1% 1% Matsu Motorcycle F-65DE 0% 0% 0% 1% 2% Matsu Motorcycle FN-80SDE 0 % 0% 0% 2% 4% Matsu motorcycle FN-100SSDE 0% 0% 1% 2% 3% Expancel 551DE40d42 0% 1% 3% 8% 16% Expancel 551DE20d60 1% 3% 7% 14% 27% Expancel 461DE20d70 0% 1% 9% 22% 38% Expancel 930DU120 0% 0% 0% 0% 57% Matsu motorcycle F-30D 2670% 3450% 4230% 4990% 5360 ° A) Matsu motorcycle F-36D 200% 1700% 3820% 4490% 5010 ° A) Matsu motorcycle F-48D 0% 1060% 2500% 2900% 3230 ° A) Expancel ratio 031DU40 / Expancel 461DE20d70 1/8 by weight 31% 36% 46% 75% 84% Expancel ratio 031DU40 / Expancel 461DE20d70 1/4 by weight 67% 78% 97% 140% 136% Expancel ratio 031DU40 / Expancel 461DE20d70 1/2 by weight 113% 127% 154% 276% 239% Expancel ratio 031DU40 / Expancel 461DE20d70 1/1 by weight 155% 178 % 205% 274% 307% Expancel 461DU20 108% 393% 9 01% 1323% 1666% Expancel 031DU40 2130% 2421% 2771% 4359% 4693% When Tgd of the liquid polymer precursor was greater than Tma, fluid-filled polymeric microspheres, the gas trapped within the microspheres Polymers diffused polymeric microspheres out of the envelope into the polyurethane matrix, causing a non-uniform and large pore size in the polishing pad, negatively affecting the polishing performance. The invention provides polishing pads having excellent stability to the packaging tool. This stability to the packaging tool can improve the life of the tampon. In addition, the mixture of pre-expanded and unexpanded polymeric microspheres allows the casting of low density polishing pads, which is not possible with conventional casting techniques. Finally, the use of a blend of pre-expanded and unexpanded polymeric microspheres can create an ideal combination of viscosity for pourability and exothermic heat for efficient pore diameters for improved polishing.

Claims (10)

REVENDICATIONS1. A method of manufacturing a polishing pad suitable for planarizing at least one of the semiconductor, optical and magnetic substrates, characterized in that the method comprises the following: obtaining a formed liquid polyurethane material from an isocyanate-terminated molecule and a curing agent, the liquid polyurethane material having a Tgei temperature and containing fluid-loaded polymeric microspheres, the fluid-loaded polymeric microspheres are a mixture of fluid-filled polymeric microspheres pre-expanded and unexpanded, the pre-expanded and unexpanded fluid-loaded polymeric microspheres both having a temperature Tar at which the diameter of the pre-expanded and unexpanded fluid-loaded polymeric microspheres increases to equal or greater than the temperature T.ba ,, and a temperature of 7 to a gas escapes through the pre-expanded and unexpanded fluid-loaded polymeric microspheres to reduce the diameter of the expanded and unexpanded fluid-laden polymeric microspheres, wherein the unexpanded fluid-laden polymeric microspheres are at the temperature Tged of the liquid polyurethane material; casting the liquid polyurethane material containing the mixture of pre-expanded and unexpanded fluid-loaded polymeric microspheres to react the isocyanate-terminated molecule and the curing agent; heating the mixture of pre-expanded and unexpanded fluid-filled polymeric microspheres in the liquid polyurethane material to a temperature of at least Tr of the unexpanded fluid-laden polymeric microspheres to increase the diameter of the fluid-loaded polymeric microspheres unexpanded, the heating being up to a temperature below the temperature Tma, at which a gas escapes through the pre-expanded and unexpanded fluid-filled polymeric microspheres, the heating being intended to form a mixture of polymeric microspheres charged with pre-expanded and expanded fluid in the liquid polyurethane material; curing the mixture of pre-expanded and expanded fluid-charged polymeric microspheres in the liquid polyurethane material to solidify the liquid polyurethane material into a polyurethane matrix containing the pre-expanded and expanded fluid-loaded polymeric microspheres; and finishing the polishing pad from the cured polyurethane matrix containing the pre-expanded and expanded fluid-loaded polymeric microspheres wherein the final diameter of the pre-expanded and expanded fluid-loaded polymeric microspheres is less than that obtained from the temperature T 'in the air and most of the fluid contained in the pre-expanded and unexpanded fluid-loaded polymeric microspheres remains in the pre-expanded and expanded fluid-laden polymeric microspheres. 2. The method of claim 1 characterized in that it includes the further step of incorporating the pre-expanded and unexpanded fluid-laden polymeric microsphere mixture into the liquid polyurethane material prior to casting. 3. Method according to any one of the preceding claims, characterized in that the temperature 7 of the polymeric microspheres loaded with unexpanded fluid is at least 5 ° C lower than the temperature T of the liquid polyurethane material. 4. Method according to any one of the preceding claims, characterized in that the casting is carried out in a cake mold for forming a polyurethane cake structure, and in that it includes the additional steps of removing the cake structure from polyurethane mold and cutting the cake structure into multiple sheets of polyurethane, and the formation of polishing pads from the polyurethane sheets. 5. Method according to any one of the preceding claims characterized in that the casting includes the pouring of the liquid polyurethane material and the mixture of pre-expanded and expanded fluid-filled polymeric microspheres around a transparent block and in that the Polishing pad formation includes a transparent window in the polishing pad. A method of manufacturing a polishing pad suitable for planarizing at least one of semiconductor, optical and magnetic substrates, characterized in that the method comprises the following: obtaining a polyurethane material A fluid formed from an isocyanate-terminated molecule and a curing agent, the liquid polyurethane material having a Tgei temperature and containing fluid-loaded polymeric microspheres, the fluid-loaded polymeric microspheres are a mixture of polymeric microspheres. pre-expanded and unexpanded fluid loaded with isobutane, isopentane or a mixture of isobutane and isopentane, the pre-expanded and unexpanded fluid-loaded polymeric microspheres each having a temperature at which the diameter of the pre-expanded and unexpanded fluid-loaded polymeric microspheres increases at temperatures equal to or greater than the Tnar temperature; and a temperature T at which gas escapes through the pre-expanded and unexpanded fluid-loaded polymeric microspheres to reduce the diameter of the expanded and unexpanded fluid-laden polymeric microspheres. the TE temperature of unexpanded fluid-charged polymeric microspheres being less than the temperature Tgd of the liquid polyurethane material; casting the liquid polyurethane material containing the mixture of pre-expanded and unexpanded fluid-loaded polymeric microspheres to react the isocyanate-terminated molecule and the curing agent; heating the mixture of pre-expanded and unexpanded fluid-loaded polymeric microspheres in the liquid polyurethane material to a temperature of at least L. unexpanded fluid-laden polymeric microspheres to increase the diameter of the polymeric microspheres charged with unexpanded fluid, the heating being up to a temperature below the temperature at which a gas escapes through the pre-expanded and unexpanded fluid-loaded polymeric microspheres, the heating being intended to form a mixture of charged polymeric microspheres pre-expanded and expanded fluid in the liquid polyurethane material; curing the mixture of pre-expanded and expanded fluid-charged polymeric microspheres in the liquid polyurethane material to solidify the liquid polyurethane material into a polyurethane matrix containing the pre-expanded and expanded fluid-loaded polymeric microspheres; and finishing the polishing pad from the cured polyurethane matrix containing the pre-expanded and expanded fluid-loaded polymeric microspheres where the final diameter of the pre-expanded and expanded fluid-loaded polymeric microspheres is less than that obtained from The temperature in the air and most of the fluid contained in the pre-expanded and unexpanded fluid-laden polymeric microspheres remain in the pre-expanded and expanded fluid-laden polymeric microspheres. The method of claim 6 characterized by including the further step of incorporating the pre-expanded and unexpanded fluid-loaded polymeric microsphere mixture into the liquid polyurethane material prior to casting. 8. Process according to any one of claims 6 and 7, characterized in that the temperature T of the unexpanded fluid-laden polymeric microspheres is at least 5 ° C lower than the temperature Tgd of the liquid polyurethane material. 9. Process according to any one of claims 6 to 8 characterized in that the casting is carried out in a cake mold to form a polyurethane cake structure, and in that it includes the additional steps of removing the structure polyurethane cake from the mold and cutting the cake structure into multiple sheets of polyurethane, and forming polishing pads from the polyurethane sheets. 10. A method according to any one of claims 6 to 9 characterized in that the casting includes the pouring of the liquid polyurethane material and the mixture of pre-expanded and expanded fluid-filled polymeric microspheres around a transparent block and in that the formation of the polishing pad includes a transparent window in the polishing pad.